YOGA AND THE CHRISTIAN
Yoga is a Hindu science that claims to teach people how to unite their soul with the "Supreme Soul", and merge their will with the "Cosmic Will".
The practice of yoga has three main components:
1) The physical exercise component,
2) The mental meditation component, and
3) The verbal chanting component.
These three are combined to make yoga what it is.
Let us think of these three separately.
1) There is nothing inherently holy or evil about the physical exercise component by itself. If someone stretches his leg in a certain way, that is neither holy nor evil. None of the physical stretching exercises in yoga need be connected with any religion. So we can do any exercise freely, even if it was a Hindu (or a Muslim, or a Buddhist) who first taught it. A typical yoga lesson does not emphasize the spiritual connection initially. So when people hear that some Christians are opposed to the practice of yoga, they wonder why. The reason is that the more advanced you get into yoga, the more you are going to move towards the ultimate purpose behind these exercises. So while breathing exercises may appear to be innocent initially, even these could be initial stepping stones that have its overall aim as "merging the individual will with the Cosmic Will."
2) When it comes to the mental meditation component, we have to be careful. Yoga typically teaches people to empty their minds of all thoughts and then to meditate. That is wrong for a Christian. The Bible tells us to meditate on God's Word at all times. We must FILL our minds with God's Word - meditating especially on the verses that tell us how much God loves us (e.g. Psalm 139:17-18, Isaiah 49:15-16, Jeremiah 29:11, etc).
3) The verbal chanting component is what we must avoid altogether. Yoga typically teaches people to keep chanting the word "Om" - a syllable that is supposed to be the highest manifestation of God-consciousness in Hinduism. The invoking of Om to relax is much more than a blind chant of some random syllable. It is an opening of the mind to other spirits. As Christians, we must never seek to achieve any sort of relaxation by such chants. We do not even chant the Name of Jesus, because that Name is not a 'mantra' - and our Lord specifically forbade us from using meaningless repetitions in prayer. The Lord gives us rest in our minds through the Holy Spirit and not by chanting.
It is best to avoid group yoga classes, as these classes are most often led by yoga instructors who subscribe to underlying yogic philosophy. Submitting to their instructions may possibly open your inner being to spirits other than the Holy Spirit, if you are not strong in the Lord. Even if you are strong in the Lord, your example may encourage weaker believers to go to such classes - and they may suffer. So, if you find that the physical exercises taught in yoga are useful to keep your body fit, you could practice them on your own in your own home. But if you find an uneasiness in your spirit in doing them, then avoid even that. There are many other forms of exercise that you can engage in, to keep yourself physically fit. We know the mind of the Spirit in all matters by peace in our hearts (Rom.8:6).